Tempted to switch to Nikon D5100

I currently have an EPL1 + 20 1.7 which I love. However my wife and I have twin girls on the way and I really want to switch back to an SLR for a number of reasons: focusing speed/overall operation, battery life, dynamic range, feel in hand, etc. The Nikon D5100 does look to be a superb choice. The EPL1 + 20 1.7 really is impressive, is this a mistake, unbiased thoughts ????